Rotary inverter and rectifier



Aug. 17, 1937. R, D] SABATINO 2,090,010

ROTARY INVERTER AND RECTIFIER Filed July 15, 1953 fiyi. 27

INVENTOR.

ATTO EYS Patented Aug. 17, 1937 UNITED STATES PATENT OFFICE 2,090,010ROTARY INVERTER AND RECTIFIER Delaware Application July 13, 1933, SerialNo. 680,205

4 Claims.

The present invention relates to a rotary inverter and rectifier, theobject of which is to provide a means for obtaining any desireduni-directional voltage from a uni-directional voltage source, andparticularly for obtaining a uni-direc-.

tional voltage higher voltage of the source.

Heretofore high uni-directional voltages have been obtained from lowuni-directional voltage sources in several ways, including. the use of avibrating reed for interrupting the low uni-directional voltage topermit its transformation to a higher alternating voltage by means of anordinary transformer, and the usual means for rectitying this highalternating voltage to obtain a high uni-directional voltage. Suchmethods have the disadvantages of mechanical instability, poor waveform, limitations to the frequency of interruptlon, and relatively shortlife. They have been used chiefly because of their economical construction. In my invention I accomplish the object of obtaining a highuni-directional Voltage from a low uni-directional voltage in such a wayas to have high mechanical stability, highly improved wave form, widerange of possible frequencies of interruption, and long life.

The attainment of the object of my invention, namely the obtaining ofhigh uni-directional voltages from low uni-directional voltage sourcesin an eiiioient and simple manner, will be apparent from the followingdescription read in conjunction with the accompanying drawing in which:

Fig. 1 is a diagrammatic view of one modification of a rotary inverterand rectifier embodying my invention;

Fig. 2 is a view of the ring 1 of Fig. 1 taken perpendicular to the axisof the shaft I0 of Fig. 1;

Figs. 3 and 4 are diagrammatic views of further modifications of arotary inverter and rectifier embodying my invention;

Fig. 5 is a view of the ring 33 of Fig. 4 taken perpendicular to theaxis of the shaft 42 of Fig. 4.

Fig. 1 is adiagrammatic viewof one modification of a rotary inverter andrectifier embodying my 15 invention. I is a motor whose terminals-2 and3 are connected to the same source whose E. M. F. it is desired tochange. I may be any other convenient source of mechanicalpower. The twometallic rings 5 and l, have the projections 6 and 0 8 respectively.Fig. 2 shows a view of one of these rings taken perpendicularly to theaxis of the shaft ill. The rings are rigidly mounted on the shaft l0(and electrically insulated therefrom),

than the uni-directional which shaft may be either an extension of the 5shaft of the motor I, as shown, or may be mechanically coupled to theshaft of the motor. The rings 5 and l are electrically insulated fromeach other in any suitable manner as for example by means of aninsulating spacer 9. The spaces between the projections 6, and thespaces between the projections 8 are both filled with an insulatingmaterial II, so as to present a continuous surface to the brushes I2,I3, I4 and I5. Rings and insulation are rigidly mounted on the shaft Illand the rotation of the motor I therefore causes the rotation of thering assembly.

Contact to the continuous portion of the ring 5 is made by means of thefixed brush l6; and contact to the ring 1 is made by means of the fixedbrush I'l. Contact to the segmented ring formed by the projections 6 andthe insulation I I is made by means of the two fixed brushes I2 and I3,which are so located that when brush I2 is over the center of one of theprojections 6, the brush I3 is over the center of one of the spacesbetween these projections. Contact to the segmented ring formed by theprojections 8 and the insulation it is made by means of the two fixedbrushes l4 and I5, which are so located that when brush it is over thecenter of one o the projections 8, brush I5 is over the center of one ofthe spaces between these projections. 7 Moreover the pair of brushes I 4and I5 is so located with respect to the pair of brushes I2 and I3, thatwhen I2 and i3 are over the centers of their respective segments, i iand I5 are over the centers of their respective segments.

The two ends of the low voltage winding. iii of the transformer it areelectrically connected to the brushes l2 and it by means of suitableelectrical conductors 2? and 28. The two ends of the high voltagewinding 29 of the transformer I8 are connected to the brushes i i andi5. One terminal of the source i is connected to the center tap 2i ofthe winding I9, and the other terminal of the source 4 is connected tothe brush I6. A switch 23 is provided for disconnecting the source 4from the inverter-rectifier. The center tap 22 of the winding 20 isconnected to the terminal 24, and the brush I1 is connected to theterminal 25. 26 is a support for the bearing for the shaft Ill, theother bearing being supplied by the motor I. The operation of theinverter-rectifier shown in Fig. 1 is as follows.

The source 4 is caused to supply power by closing with switch 23. Thiscauses the motor 1 to rotate and applies the voltage of the source 4between the center tap 2i of the winding l9 and the brush iii. If thepolarity of the source is as indicated in Fig. 1, then the center tap 2|of the winding l9 will be positive, and the brush l6 (and hence 'thering 5 and the projections 6) will be negative. Consider the instantwhen the position of the rings is as indicated in Fig. 1. In this case 5brush i2 is in contact with a projection 6 and 30 executes a completecycle as the hence will be negative. Brush from the rings. Hence therewill be a flow of electric current through one half of the winding 19,and a magnetic flux is established which links both windings l9 and 20.As the motor rotates, the brush I2 will become insulated, and brush l3will make contact with a projection 6. At that time current will flowthrough the other half of the winding l9 and again establish a magneticflux which links both windings l9 and 26. Since the center tap 2| isalways positive, the flux established by current flowing through onehalf of the winding 19 is opposite in direction to the flux establishedby current flowing through the other half of the winding 19. Hence asthe flow of current changes from one half of the winding l9 to the otherhalf, due to the rotation of the motor as described, the flux linkingthe two windings l9 and 20 reverses in direction. This reversal occursevery time the segment with which the brush I2 is in contact, changesfrom a conducting segment 6 to an insulating segment ll, and/or from aninsulating segment H to a conducting segment 6. Therefore the magneticflux segment in contact with the brush 12 changes from a conductingsegment 6 to the next conducting segment 6, or

from an insulating segment H to the next insulating segment H. Hence ifthere are 11!. conducting segments 6, and the speed of the motor is nrevolutions per second, there will be established in the transformer 18an alternating flux having a frequency of 11m cycles per second. Therewill thus be transformer action, and if the winding 26 has a greaternumber of turns than winding 19, the alternating voltage induced inwinding 20 will be greater than the voltage applied to the winding 19.

Due to the connections described, this higher alternating voltage isapplied to the brushes l4 and I5. Suppose that the relative directionsof the windings l9 and 20 are such that the polarity of the winding 26at the instant indicated in Fig. 1 is as shown. In this case brush I5 ison an insulating segment H and is inactive. Brush l4 makes contact withone of the segments 8, and it causes the segment 8, the ring 1, thebrush l1, and the terminal25 to be negative. The center tap 22 ispositive with respect to the brush l4, and hence terminal 24 is positivewith respect to terminal 25. As the motor rotates and reverses thedirection of the flux in the transformer l8, as described, the brush l4becomes positive and the brush l5 negative. At the same time the segmentin contact with the brush l4 changes to an insulating segment H, and thesegment in contact with the brush 15 changes to a conducting segment 8.The ring 1, brush l1, and terminal 25, will thus again be negative, and5 since the center tap 22 is now positive with respect to the brush l5,terminal 24 will again be positive with respect to the terminal 25.There will thus exist a high uni-directional difference of potentialbetween terminals 24 and 25, which may be either directly utilized, orfdtered by means of the well known electric low pass wave filter,

Fig. 3 is a diagrammatic view of another modification embodying myinvention. 29 is a motor 5 whose terminals are connected to any suitablesource of electric power. In this case the terminals 3| and 30arecon'nected to the same source of uni-directional voltage 32, whosevoltage it is desired to change. 29 may be any other convenient sourceof mechanical power. A metallic ring 33, with projections 34 and 35, isrigidly mounted on the shaft 42, and electrically insulated' therefrom.This shaft may either be integral with the motor shaft (as shown), ormay be a separate shaft suitably coupled to the motor shaft. The spacesbetween the segments 34, and the spaces between the segments 35, arefilled with insulating material 36 in such a way that a continuoussurface is presented to the brushes 31, 38, 46 and 4|. Electricalcontact to the segments 34 is made by means of two fixed brushes 31 and3B which are so contact with a conducting segment 34, 38 is in contactwith an insulating segment 36. Electrical contact to the segments 35 ismade by fixed brushes 40 and 4|, which are so located that when 40 is incontact with a conducting segment 35, 4| is in contact with aninsulating segment 36. Electrical contact to the continuous portion ofthe ring 33 is made by means of the fixed brush 39.

The two ends of the low voltage winding 44 of the transformer 43 areconnected, by means of suitable electrical conductors, to the brushes 31and 38. The two ends of the high voltage winding 45 are similarlyconnected to the two brushes 46 and 4|. The center tap 46 of the winding44 is similarly connected to one terminal of the source 32. The otherterminal of the source 32 is similarly connected both to the brush 39,and to the terminal 48. The center winding 45 is similarly connected tothe terminal 49. A switch 53 is provided for disconnecting the source 32from the inverter rectifier. The operation of this form of my inventionis as follows.

The switch 50 is closed so as to permit the flow of current from thesource 32. This causes the motor 29 to rotate. At the same time itcauses the voltage of the source 32 to be applied between the center tap46 of the winding 44, and the 'brush 33. Assuming the polarity of thesource to be as shown, the center tap 46 will be positive, and the brush33 and the terminal 48 will be negative. The'metallic ring 33 will thusalways be negative with respect to the center tap 46. When the positionof the ring is as shown in Fig. 3, the brush 39, and hence the end ofthe winding 44 to which it is connected through located that when 31 isin tap 41 of the brush 31, is negative, and current will flow in onehalf of the winding 44. This current will set up a magnetic flux intransformer 43 which will link both windings 44 and 45. As the ringrotates, the segment in contact with the brush 31 will change to aninsulating segment 36, and the segment in contact with the brush 38 willchange to a conducting segment 34. This causes the current alreadyflowing to cease, and by making the brush 38 negative with respect tothe center tap 46, causes the current to flow in the other half of thewinding 44. As before, a magnetic flux linking 44 and 45 will again beestablished. Inasmuch, however, as the center tap 46 is always positivewith respect to the other end of that half of the winding 44 in whichcurrent is flowing, the flux set up by the current in one half of thewinding 44 is opposite in direction to the flux set up by the current inthe other half of the same winding. Hence as the current changes fromone half of the winding 44 to the other half, due to rotation of thering, the flux reverses its direction. Such a reversal occurs every timethe segment under brush 31' changes from a conducting segment 34 to aninsulating segment 35, or vice versa. The flux will, therefore undergo acomplete cycle every time the segment under 31 changes from a conductingsegment 34 to the next conducting segment 34, from an insulating segment36 to the next insulating segment 36. Thus if there are m conductingsegments, the flux undergoes m complete cycles per revolution, and ifthe speed oi. the motor 29 is n revolutions per second. the alternatingflux established in the transformer 43 will have a frequency of nmcycles per second. Due to ordinary transformer action, this alterhatingflux will induce a corresponding alternating voltage in the high voltagewinding 45, and if the number of turns in 45 is greater than the numberof turns in 44, the voltage in the secondary winding 45 will be higherthan the voltage applied on 44. This induced high voltage will existbetween the brushes 40 and 4|. Suppose that the relative directions ofthe windings 44 and 45 are such that at the instant indicated in Fig. 3the polarity of the induced voltage is as shown. Then brush 40 isnegative with respect to brush 4 I. In this case the centertap 4Lispositive with respect to brush 40; and since brush 40 is making contactwith the ring 33, it is at the same potential as the terminal 48 becauseofthe connections described. The center tap 41, and hence the terminal49, will be positive with respect to the terminal 48, and between theterminals 48 and 49 will exist a voltage equal to the voltage induced inone half of the winding 45. As the ring 33 rotates, it causes thereversal of the flux in transformer 43, as described, and therefore ofthe polarity of the voltage induced in 45. The brush 43 will now becomepositive, and brush 4! negative. This same rotation, however,simultaneously causes the segment under 40 to change to an insulatingsegment 36, and the segment under 4| to change to a conducting segment35. The ring 33 will thus again be negative with re- 45 spect to thecenter tap 41. Therefore terminal 48 will again be negative with respectto the terminal 49. There will thus exist between terminals 48 and 49 aunidirectional difference of of the well known electric low pass Wavefilter.

An alternate form of the ring 33 (of Fig. 3) with its projectingsegments, is shown in Figs. 4 and 5, Fig. 4 being a diagrammatic axialview, and Fig. 5 being a view taken perpendicularly to the axis of theshaft 42. Instead of having a set of projections on either side of thering, a single set of projections, and on one side only, is provided, asshown in Fig. 4. Since the projections 34, in Fig. 3, are at the samepotential as the projections 35, this change in no way afiects theoperation of the unit, but merely involves placing the brushes 3'! and38 on the same side of the ring 33, as the brushes 40 and 4!, asindicated in Figs. 4 and 5. The rest of the circuit, and the connectionsto the brushes, as well as the operation of the inverter rectifier,remain absolutely and identically the same and unchanged, and are thesame as described for Fig. 3. It is obvious that minor modifications maybe made in the above descriptions without departing from-the spirit ofmy invention. All of the above forms of my invention involve twosteps-the changing of a unidirectional voltage into an alternatingvoltage, and the changing of this alternating voltage into aunidirectional voltage. Furthermore the above descriptions have all beenplied to the primary of the transformer, this being the most usual case.If however, due to any difference in phase it is found necessary toadjust the time of reversal of the secondary connections with respect tothat of the reversal of the primary connections, to avoid suchundesirable effects as sparking, this may be accomplished very easily,in all the connecting to the justments permit the use of any type ofimpedance load.

What I claim and desire to protect by Letters Patent is: I

1. In combination with a source 01 unidirectional voltage, a transformerhaving primary and secondary windings, each provided with anintermediate tap; one terminal of the source to the intermediate primarytap; means for alternately connecting the terminals of the primarywinding to the other terminal of the source, the last named meansternately engageable by the commutator segments; and means forrectifying the secondary output comprising a second rotating set ofelectrically connected commutator segments electrically connected to thefirst set, and a pair of brushes connected to the terminals of thesecondary winding and alternately engageable by the commutator segments,the commutator segments engaging the last named brushes in timedrelationship with the alternations of primary current flow whereby afull wave rectified voltage is obtained between the last namedcommutator segments and the intermediate secondary tap.

2. In combination with a source of unidirectional voltage, a transformerhaving primary and secondary windings, each provided with anintermediate tap; means continuously connecting oneterminal of thesource to the intermediate primary tap; means for alternately connectingthe terminals of the primary winding to the other terminal of thesource, the last named means comprising a rotatin set of electricallyconnected commutator segments, means continsegments;

the terminals of the second winding to the commutator segments whereby afull wave rectified voltage is obtained between the commutator segmentsand the intermediate secondary tap.

3. In combination with a source of unidirectional voltage, a transformerhaving primary and secondary windings, each provided with anintermediate tap; means continuously connectlng one terminal of thesource to the intermediate primary tap; means for alternately connectingthe terminals of the primary winding to the other terminal of thesource,the last named means comprising a rotating set of electricallyconnected commutator segments, means continuously means continuouslyconnecting joining the last named terminal of the source to thesegments, and a pair of brushes connected to the terminals of theprimary winding and alternately engageable by the commutator segments,and means for rectifying the secondary output comprising meansintermittently connecting the terminals of the secondary winding tothose of the primary winding in timed relationship to the alternationsof current flow in the primary winding whereby a full wave rectifiedvoltage is obtained between the commutator segments and the intermediatesecondary tap.

4. In combination with a source of unidirectional voltage, a transformerhaving primary and secondary windings, each provided with anintermediate tap; means continuously connecting one terminal of thesource to the intermediate primary tap; means for alternately connectingthe terminals of the primary winding to the other terminal of thesource, the last means comprising a rotating slip ring and a pluralityof commutator segments rotating nected thereto, a brush connected to thelast named terminal of the source and continuously engaging the slipring, and a pair of brushes connected to the terminals of the primarywinding and alternately engageable by the commutator segments; and meansfor rectifying the secondary output comprising a second pair of brushesconnected to the terminals of the secondary winding andalternatelyengageable by the commutator segments, whereby a full wave rectifiedvoltage is obtained between the first mentioned brush and theintermediate secondary tap.

ROLAND DI SABATINO. f

therewith and electrically conv

